1. Field of the Invention
The present invention relates to energy saving of a data transfer apparatus as a network interface for a printer, a copier, a MFP (multi-function peripheral) or such, and in particular, to a data transfer apparatus carrying out energy saving control and an image forming apparatus employing such a data transfer apparatus.
2. Description of the Related Art
As a system considering power saving, Japanese Laid-open Patent Applications Nos. 11-085420 and 2002-111927 disclose related arts. Japanese Laid-open Patent Application No. 11-085420 discloses a printing system in which a host apparatus and a printing apparatus connected with the host apparatus via a communication network are provided, and the printing apparatus receives printing data from the host apparatus and prints out the same. In this system, the host apparatus is connected with the printing apparatus in a bi-directional communication manner; the printing apparatus has a means for entering a power saving mode after an elapse of a predetermined time period, a means for releasing from the energy saving mode when receiving transmission data from the host apparatus, a means for obtaining energy saving setting time information based on energy saving status information obtained in the bi-directional communication manner, and a means for transmitting corresponding information to the host apparatus instantaneously when entering the energy saving mode. The host apparatus has an application tool started up in the host apparatus for producing image data to transmit to the printing apparatus, an operation panel displaying a button for releasing from the energy saving mode on a page of the application, and a means for transmitting data to the side of the printing apparatus for releasing it from the energy saving mode in response to an instruction input from the releasing button. In this system, from a time at which the releasing button is pressed, a time period is calculated, the host apparatus recognizes a setting time based on the setting time information for entering the energy saving mode, and re-displays the releasing button on the operation panel before the above-mentioned time has elapsed.
Japanese Laid-open Patent Application No. 2002-111927 discloses a facsimile apparatus including a facsimile communication part carrying out facsimile communication via a public communication line, and a LAN (Local Area Network) interface part carrying out communication by means of electronic mails via the LAN. The LAN interface part has a control means, switching thereof of which is available between a regular operation mode in which a program is operated at a regular clock frequency and communication is carried out between the facsimile communication part and the LAN; and a low power mode in which the clock signal is stopped, and the program is halted. The control means is switched into the low power mode when, in the regular operation mode, a series of processing operation is finished, and then, is switched into the regular operation mode when a stating-up signal is received from the LAN or the facsimile communication part.
In the above-mentioned system disclosed by Japanese Laid-open Patent Application No. 11-085420, once the host is informed that the printing apparatus enters the energy saving mode, and then, when the energy saving releasing button is pressed from the host, the energy saving releasing data is transmitted to the printing apparatus for releasing from the energy saving mode. In this configuration, an application for carrying out the energy saving control is required on the host side.
In the above-mentioned system disclosed by Japanese Laid-open Patent Application No. 2002-111927, the facsimile apparatus automatically enters the regular operation mode from the energy saving mode when the started-up signal is received from the LAN I/F part. In this system, since the starting-up signal has an IP address of the facsimile apparatus itself, the facsimile apparatus is released from the energy saving mode into the regular operation mode when receiving any packet directed to the facsimile apparatus itself regardless of the actual contents of the packet. Accordingly, the energy saving effect may not substantially work.
An image forming apparatus such as a printer, a copier, an MFP or such, is required to be configured so that, it can be directly connected to an external apparatus such as a PC (personal computer). For this purpose, such an apparatus has an interface for being connected to the external apparatus such as a PC for when the necessity arises.
The above-described system disclosed by each of Japanese Laid-open Patent Applications Nos. 11-085420 and 2002-111927 is configured for energy saving for a case where the printing apparatus or the facsimile apparatus is always connected to the external apparatus via the communication network. However, these systems may not be configured in consideration of such a situation that energy saving should be carried out even in an apparatus having an interface prepared for being connected to the external apparatus such as a PC for when the necessity arises.